Photoinduced electron-transfer reactions: a study of the diffusion-controlled and activation-diffusion-controlled...

Area of Science:

• Photochemistry
• Physical Chemistry
• Inorganic Chemistry

Background:

• Electron transfer reactions are fundamental in chemical processes.
• Ruthenium complexes are widely studied for their photochemical properties.
• Understanding diffusion-controlled reactions is crucial for kinetics.

Purpose of the Study:

• To experimentally determine electron transfer rate constants for ruthenium complexes.
• To calculate effective viscosity coefficients of sodium nitrate solutions.
• To validate theoretical models for electron transfer reactions.

Main Methods:

• Experimental determination of rate constants for ruthenium complex quenching reactions.
• Calculation of viscosity coefficients using Exponential Mean Spherical Approximation (EMSA) and Eigen-Fuoss (EF) models.
• Validation using rate constant calculations for iridium and ruthenium complexes and fluorescence quenching measurements.

Main Results:

• Experimental and predicted rate constants showed excellent agreement.
• Trends in association and dissociation rate constants were analyzed.
• Effective diffusion coefficients were used to derive intrinsic electron transfer rate constants.

Conclusions:

• The study successfully modeled diffusion-controlled electron transfer.
• Marcus electron-transfer treatment effectively rationalized observed trends.
• The methodology provides a reliable approach for studying electron transfer kinetics.